Automatic firearm



May 20, 1930. BIETHEL-ABIEL REVELLI AUTOMATIC FIREARM Filed March 21.1928 2 Sheets-Sheet 1 Fig. 1a

May 20, 1930. BETHEL-ABIEL REVELLI AUTOMAT IC FIREARM Filed March 21.1928 2 Sheets-Sheet 2 Fig. 2

Patented May 20, 1930 UNITED, "STATES Parent OFFICE BETHEL-ABIELBEVELLI, OF TURIN, ITALY, ASSIGNOR TO ARMAMENTI MILITARI S. A., OFTURIN, ITALY AUTOMATIC FIREARM Application filed March 21, 1928, SerialNo. 268,288, and in Great Britain August 25, 1927.

This invention relates to improvements in machine guns and hke automaticfirearms.

One object of the present invention is to provide automatic firearmswhich are sim- 5 pler and cheaper 'to construct than those commonl inuse. I

A furt er object is to provide a fire. arm of which the weight is lessthanthat of mod ern machine guns.

10 The improvements consist principally in that the breech closure isobtained, as in small automatic pistons, by means of the weight ofethebreech block combined with the action of a spring pressing it forward,

[5 thuskeeping the breech block of a moderate weight and size even whenwar cartridges are used. v

The invention consists in the combination of means whereby thepercussion is effected in advance of, i. e. a little before the completeclosure of the breech block so that this. latter is still moving forwardto close the breech at the moment of discharge with means whereby thepressure of the exploded charge I is admitted to aspace in the chambersurrounding the neckof the cartridge so as to balance the-internalpressure thereon. It is known that it is not broadly new to operate ahammer carried by the breech block :0 by means of a stop on the fixedbreech casing at the moment when the breech closes.

The balancing of pressure on the cartridge neck is attained by specialarrangements consisting in that the cartridge is fully con- 5 tained inthe barrel chamber so that the base of the cartridge case will notbedeformed during recoil and in that in said chamber longitudinalrectilinear or curved grooves [are provided in order to create, by meansof 0 the gases at the moment of discharge, a counter pressure directedinwardly onto the neck the closure, are dispensed with, means beingprovided for automatically displacing the extractor hook at; the end ofthe forward stroke of the breech block thus obtaining the advantage ofavoiding any risk of breaking the extractor end as happens sometimes inknown automatic firearms owing to the escape of gas caused by defectivecartridge cases breaking when firing;-

The accompanying drawing shows by way of example a constructional formof the improved fire arm according to this invention. On the drawing thearm is provided with a butt to enable its use as a rifle. When it isdesired to mount it on a support for use as a machine gun, the buttwhich, however, does with a handle.

Figures 1, 1 and 1 show a horizontal longitudinal section of the firearm, the breech block being in the closed position.

Figures 2 and 2 show alongitudinal vertical section of the fire arm, thebreech block being in the cooked position.

Figure 3 is a detailed view of the fire arm as the breech block movesforward and a cartridge is entering the cartridge chamber guided by aspecial device adapted to facilitate its introduction.

Figure 4 is a cross vertical sectionshowing how the barrel is fittedinto the plug and held in this position.

. Figure 5 shows a modified method of fastening the striker lever.

Figure 6 shows a further construction in which the lever itself,modified in shape and position, forms the striker.

Figure 7 shows the pivots used for this fire arm and removable withoutemploying any special tools. A I

Figure- 8 shows diagrammatically the action of the gas pressure on thecartridge case on firing.

1 denotes the barrel and 2 denotes the breech formed from a tube (forinstance a Mannesmann tube) closed at its front end by a plug 3, towhich the barrel is fitted by means of a bayonet jointand safety look,as

hereinafter described. A 'sleeve 4 surround- (not hinder such use of theweapon, will be ing the barrel is fixed to the plug 3 and is supportedat its front end by a support 5 carried by the barrel.

The bayonet joint (Figure 4) comprises teeth or fins 1 on the barrel andlongitudinal grooves 3 on the plug. This latter carries. further at theend of the grooves 3' a circular cross groove receiving the teeth 1'when the barrel is rotated. The barrel is locked in position by means ofa tooth 46 on a lever 46 pivoted to the sleeve 4 and subjected to theaction of a spring 47. The tooth 46 is forced between two teeth 1 on thebarrel and locks this latter; in order to release it, the lever 46 isacted upon against the action of the spring 47. The breech block 6 is ofcylindrical form and is slidably mounted in the breech and at its rearportion the block is provided with a projection 6 of smaller diameterserving as a guide for a return spring 7 which abuts against a rear plug8 of the breech. The breech block can be made of suitable weight withoutenlarging its size by filling a recess thereof with a mass of heavymaterial, e. g. a Wolfram block. lVIoreover means can be provided foradjusting from the outside the tension of the return spring inaccordance with the inclination of the fire arm (more particularly forfiring against aircraft).

The breech block is provided with a handle 9 comprising a stem fittinginto a correspond-- ing slot on the breech bolt to which it is securedby means of a pin 10 which after the breech block has been mounted inthe breech, is passed through a hole 11v (Figure 2) in said breech. Thehandle 9 slides in a rectilinear slot 13 formed in the breech, whichslot, as clearly shown in Figure 1, does not extend to the breech ends.The striker 12 is slid-ably mounted in the front portion of the breechblock and is normally maintained in the inoperative position by a spring14; the striker is operated by means of a lever 15 pivoted in 16 to thebreech block and which does not extend beyond the widest circumferenceof the breech block. One arm of the lever 15 is adapted when the breechblock has nearly completed its forward stroke to strike against a lug 17forming part of an ejector 17 secured to the breech and extending into acorresponding slot 18 formed in the breech block whereby the striker iscaused to move forward and effect the striking; the arrangement is suchthat there is a slight advance in the striking which admits of thefiring taking place while the breech block still possesses a certainmomentum in the direction of its closing movement, this ensuring theclosure without special members and without excessive weight of thebreech block.

Figure 5 shows a modified arrangement of the lever 15 which instead ofoscillating about the pivot 16 carried by the breech block rocks by itsprojection 15 in a recess formed in the handle 9. This simplifies theconstruction and facilitates removing and controlling the lever 15 thatis fitted in and extracted in a single operation by the handle 9.

According to the modified construction shown. in Figure .6, the saidlever is dispensed' with and replaced by a lever 48 pivoted through apivot 49 to the front end of the breech block and pressed by a spring50. The striker 12 is also dispensed with, its action being performed bythe projection 48 of a lever 48, abutting by a projection 48", as thebreech block reaches the end of its stroke, against the front plug 2 ofthe breech, whereby the lever is caused to oscillate and striking iseffected.

The barrel chamber is formed with longitudinal grooves 45 (measuring indepth and width a few tenths of a millimeter) which extend from thepoint at which the chamber becomes narrower to receive the neck of thecartridge case to about a millimeter beyond the point reached by theneck. The cartridge case which is fully contained inthe barrel, as shownin Fig. 1, is subjected on the outer side of the neck to the gaspressure during firing and first part of the recoil so that thecartridge cannot be deformed, the arrangement being such that there isno risk of escape of gas.

As shown in Figure 8, when recoil begins and the gas pressure still actson the cartridge case, a force C is exerted on the neck of this latter,of which the horizontal component B has a direction opposite to the iforce A acting on the base. These two forces A and 13 cause anelongation of the cartridge case which therefore breaks easily where thestresses are greater, namely in proximity to the base. This seriousdrawback as well as the deformation of the neck is fully eliminated inthis fire arm by virtue of the grooves 45 admitting of the gases toproduce a pressure on the neck outside the cartridge case, annulling bya force D the 3 force B opposing the force A.

The extractor 19 comprises a tooth 20, which, during the last short partof the forward stroke of the breech block, slides on an inclined surface21 formed on the barrel 3 and isthereby forced to pivot, thus moving theextractor hook 19' away from the cartridge edge and therefore from thebarrel chamber.

The loader 22 is adapted to receive two i series of cartridges and isprovided with a The loader is I In order to facilitate the feeding ofthe I cartridges taken in turns from the two series of cartridges in theloader by the breech block during its forward movement, there isprovided a guide 25' pivotally mounted in 26 on the breech and providedwith a hollow cradle-like surface (Figure 2) which directs thecartridges towards the barrel chamber, (Fig. 3). The guide 25 isoperated by formed on the breech block and in engagement with the pins28. A cavity 31 into which the guide may enter when lowered is providedunder the barrel chamber in the plugl3.

T e breech block is provided with longitudinal grooves 42 on its wholeperiphery so that dust or other foreign matter entering the breech willenter the grooves without creating any resistance to the sliding of thebreech block.

' A case 32 containing the trigger mechanism is soldered or otherwisesecured to the breech. The said mechanism comprises a trigger 33 urged.upon by a spring 34 and an operating lever 35 which is operated by thesaid trigger and which, when the trigger is released, retains the breechblock in the cooked position by engagement with a slot formed in thebreech block as shown in Figure- 2, a single spring acting simultaneousy on the trigger and on the trigger lever.

The firearm butt 36 is mounted on the rear breech plug against which itis resiliently pressed by a spring 37 the plug is provided with a flangehaving two diametrically opposed holes 38 adapted toreceive twocorresponding pins 39 carried by a metallic flange integral with thebutt 36. When it is desired to move the butt from the normal position tothe foverturned position to facilitate firing at a certain elevationwhen the gunner lies on the ground the butt-is pulled rearwardly againstthe action of the s ring and rotated through 180 and is then a1 owed tosnap into locked position by the entering of the pins into the holesformed in the plug. The rear In is provided with an annular buffer orshock absorber 40 to check the rearward motion of the breech block 6.The front part of the barrel sleeve is provided with a pedestal (nonillustrated for-simplicitys sake) the legs of which may be overturned orfolded over on to the sleeve during of a ball joint. sponding to thepositions;

The firearm is as usual provided with 8.

provided with stops correuse and transportation efi'ect this the legsare articulated v handle 41 which in the normal position is bebind thetrigger.

In order to facilitate mounting and relarger diameter than the pivot,but when it is closed it does not exceed thesaid diameter.

For placing the pivot 51 in, position, the pivot is placed by its outerend against the opening of its seat, of which the ends are slightlyflared, and is pressed upon in' order to force the ring 52 against theflared end, causing the ring 52 to close and enter the groove 51'; thepivot is driven through the hole and issues at the other end where theresilient rin again expands preventing the pivot from ecoming loose. Apressure 1n the opposite direction will'eifect removal of the pivot. Thecharacteristic feature of this look is that the ring never leaves thepivot and.cannot be lost, which is of great importance when using thefire arm on the field.

What I claim is: v

1. A machine gun comprising, in combination with a breech boltof'whichthe closure is obtained by virtue of its weight a striker carried bysaid bolt, a stop member on the breech, a lever co-operating with saidstop member for actuating said striker before the breech bolt hasreached the end of its closing stroke, a barrel chamber havinglongitudinal grooves corresponding with the neck portion of thecartridge case to generate, when the charge explodes, a counter-pressureon said neck portion, the length of said chamber being such that itcompletely embraces said striker before the breech bolt has reached theend of its closing stroke, a barrel chamber having longitudinal groovesin correspondence with the neck portion of the cartridge case forgenerating, when the charge explodes, a counter-pressure on said .neckportion, the length of said chamberbeing such that it completelyembraces the caras transportation of the firearm and in order to tridgecase and its edge being free of notches,

an ejector mounted for oscillating on the breech bolt and having a toothon its front end, an, inclined surface onthe. breech cooperating withsaid tooth for withdrawing the extractor from the barrel chamber whenthe breech bolt closes, anda spring for returning the extractor to itsworking position as soon as the breech bolt begins to reccdeQ 3. Amachine gun comprising, in combination with the breech having aslotclosed at both its ends and a breech bolt of which the closure isobtained by virtue of its Weight,a handle detachably mounted on saidbreech bolt, the shank of said handle being engaged by said slot, astriker mounted in said breech block, and means for preventing thedeformation of the cartridge at the beginning of the recoil movement,said means comprising longitudinal grooves formed on the wall of thefront end of the cartridge chamber of the barrel adapted to create whenfiring a-counter pressure directed inwardly on to the neck of thecartridge case, and means for actuating the striker just before the endof the closing movement of the breech block, which still possesses acertain momentum, in the direction of its closing movement ensuring theclosure. W

4. A machine gun comprising, in combination with the breech having aslot closed at both its ends and a breech bolt of which the closure isobtained by virtue of its weight, of a handle detachably connected tosaid breech bolt and having a shank engaged by said slot,

a striker lever mounted on the front portion of the breech bolt, one armof said lever acting as striker, a spring normally holding said strikerin its withdrawn position, a stop member on said breech with which theother arm of said striker lever co-operates at the end of the closingstroke of the breech bolt, a barrel chamber having'longitudinal groovesin correspondence with the neck portion of the cartridge case forgenerating, when the charge explodes, acounter-pressure on said neckportion, the length of said chamber being such that it completelyembraces the cartridge case and its edge being free of notches, anejector mounted for oscillating on the breech bolt and having-a tooth onits front end, an inclined surface'on the breech co-opcrating with saidtooth for withdrawing the extractor from the barrel chamber when thebreech bolt closes, and a spring for returning.

the extractor to its working position as soon as the breech bolt beginsto recede.

In testimony that I claim the foregoing as my invention, I have signedmy name.

BETHEL-ABIEL REVELLI.

